aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorDerek Fults <dfults@sgi.com>2006-12-07 04:37:11 (GMT)
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-07 16:39:35 (GMT)
commit22f2e280179946b8be1e2205b8654f2cb4abbf64 (patch)
treebf40a2070381fc83a365eff736763264c466db16
parent8f63fdbbd6de7d734c036948bf7c4b2bebe3ad99 (diff)
[PATCH] get_options to allow a hypenated range for isolcpus
This allows a hyphenated range of positive numbers in the string passed to command line helper function, get_options. Currently the command line option "isolcpus=" takes as its argument a list of cpus. Format: <cpu number>,...,<cpu number> Valid values of <cpu_number> include all cpus, 0 to "number of CPUs in system - 1". This can get extremely long when isolating the majority of cpus on a large system. The kernel isolcpus code would not need any changing to use this feature. To use it, the change would be in the command line format for 'isolcpus=' Format: <cpu number>,...,<cpu number> or <cpu number>-<cpu number> (must be a positive range in ascending order.) or a mixture <cpu number>,...,<cpu number>-<cpu number> Signed-off-by: Derek Fults <dfults@sgi.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--Documentation/kernel-parameters.txt7
-rw-r--r--lib/cmdline.c35
2 files changed, 40 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1e183bd..8fe6b83 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -714,7 +714,12 @@ and is between 256 and 4096 characters. It is defined in the file
Format: <RDP>,<reset>,<pci_scan>,<verbosity>
isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
- Format: <cpu number>,...,<cpu number>
+ Format:
+ <cpu number>,...,<cpu number>
+ or
+ <cpu number>-<cpu number> (must be a positive range in ascending order)
+ or a mixture
+ <cpu number>,...,<cpu number>-<cpu number>
This option can be used to specify one or more CPUs
to isolate from the general SMP balancing and scheduling
algorithms. The only way to move a process onto or off
diff --git a/lib/cmdline.c b/lib/cmdline.c
index 0331ed82..8a5b530 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -16,6 +16,23 @@
#include <linux/kernel.h>
#include <linux/string.h>
+/*
+ * If a hyphen was found in get_option, this will handle the
+ * range of numbers, M-N. This will expand the range and insert
+ * the values[M, M+1, ..., N] into the ints array in get_options.
+ */
+
+static int get_range(char **str, int *pint)
+{
+ int x, inc_counter, upper_range;
+
+ (*str)++;
+ upper_range = simple_strtol((*str), NULL, 0);
+ inc_counter = upper_range - *pint;
+ for (x = *pint; x < upper_range; x++)
+ *pint++ = x;
+ return inc_counter;
+}
/**
* get_option - Parse integer from an option string
@@ -29,6 +46,7 @@
* 0 : no int in string
* 1 : int found, no subsequent comma
* 2 : int found including a subsequent comma
+ * 3 : hyphen found to denote a range
*/
int get_option (char **str, int *pint)
@@ -44,6 +62,8 @@ int get_option (char **str, int *pint)
(*str)++;
return 2;
}
+ if (**str == '-')
+ return 3;
return 1;
}
@@ -55,7 +75,8 @@ int get_option (char **str, int *pint)
* @ints: integer array
*
* This function parses a string containing a comma-separated
- * list of integers. The parse halts when the array is
+ * list of integers, a hyphen-separated range of _positive_ integers,
+ * or a combination of both. The parse halts when the array is
* full, or when no more numbers can be retrieved from the
* string.
*
@@ -72,6 +93,18 @@ char *get_options(const char *str, int nints, int *ints)
res = get_option ((char **)&str, ints + i);
if (res == 0)
break;
+ if (res == 3) {
+ int range_nums;
+ range_nums = get_range((char **)&str, ints + i);
+ if (range_nums < 0)
+ break;
+ /*
+ * Decrement the result by one to leave out the
+ * last number in the range. The next iteration
+ * will handle the upper number in the range
+ */
+ i += (range_nums - 1);
+ }
i++;
if (res == 1)
break;

Privacy Policy